import numpy as np
import pandas as pd

a = pd.DataFrame({'one': pd.Series([1,2,3], index=['a', 'b', 'c']), 'two': pd.Series([4,5,6,7], index=['a', 'b', 'c',' d'])})

print(a)
print(a['one']['a'])
print(a.loc['a', 'one'])
print(a.loc['a',])
